1. Field of the Invention
The present invention relates to a translucent-image, display apparatus for displaying a translucent image on a screen, a method for displaying a translucent image, and a pre-recorded and computer-readable storage medium.
2. Description of the Related Art
A type of conventional video game system for executing a video game uses visual effects for a game player by displaying rays, electricity, flames, sparks, and so forth, on a screen. Many of the objects (object images and pictures) such as the rays and the electricity are translucently displayed on the screen by a translucent-image display function provided for the video game system. In addition, some types of video game system are designed to display the translucent image of an object by using any one of the following techniques: subtraction; averaging; first addition; and second addition. Subtraction is a technique in which 100% of the red, green and blue (RGB) brightness levels of the color of an object (e.g., electricity, spark, etc.) are respectively subtracted from 100% of the RGB brightness levels of the color of a base (e.g., the background of the game space).
Averaging is a technique in which 50% of the RGB brightness levels of the color of the object are respectively added to 50% of the RGB brightness levels of the color of the base.
First addition is a technique in which 100% of the RGB brightness levels of the color of the object are respectively added to 100% the RGB brightness levels of the color of the base.
Second addition is a technique in which 25% of the RGB. brightness levels of the color of the object are respectively added to 100% of the RGB brightness levels of the color of the base.
The translucent-image display function performed by the video game system consists of the above-described four techniques, and accordingly has the following problems:
According to first addition and second addition, when the color of the base is bright, in many cases, the processed results are a color in which each of the RGB brightness levels is approximately 100%, i.e. the color is white (R:100%; G:100%; B:100%). Consequently, the color of the object, which is displayed as a translucent image, is frequently a shadeless color or white. In many cases, with the shadeless color and white, the desired visual effects by displaying the translucent image of the object cannot be obtained. Accordingly, when the translucent image of the object is displayed by first addition or second addition, the color of the object must be set to a bright color beforehand. In other words, when the game space is designed to have a bright image by, for example, using a bright color for the background as a base, the translucent-image display cannot effectively be used.
The above-described four techniques also have a problem in which the color of the object frequently differs before and after the object is translucently displayed. Accordingly, when the color of the translucent image of the object is set to an arbitrary color, it is necessary to set the colors of the base and the translucent image of the object beforehand, which is complicated.